The research of a neurocomputer having a function similar to an information processing ability of an organism system has been intensively carried out these days. The neurocomputer is said to be superior in an intellectual information processing function such as association, reasoning, learning, etc. to a conventional von Neumann type computer, and has been proposed on pages 39 to 45 of "the technical research report OQE 87-174, 1988 in the Institute of Electronics Informations and Communications Engineers". The neurocomputer comprises input terminals to which a partial input signal is supplied, plural light emitting diode arrays each connected to the input terminals to be driven by the partial input signal, plural space modulation matrices each receiving lights from a corresponding array of the plural light emitting diode arrays, plural optical detector arrays each array detecting transmitting lights from a corresponding space modulation matrix of the plural space modulation matrices, differential amplifiers for generating differential electric signals by receiving electric signals dependent on the transmitting lights of the plural space modulation matrices from the plural optical detector arrays, thresholding devices for generating threshold signals in accordance with the thresholding of the differential electric signals, and output terminals to which the input terminals and the thresholding devices are connected in parallel to provide a complete output signal. Each of the space modulation matrices includes 32.times.32 glass dry plates of an emulsion type into which information of white and black is written to provide a predetermined pattern, so that the plural space modulation matrices have different information patterns from each other.
In operation, the partial input signal is supplied to the input terminals, so that the plural light emitting diode arrays are driven to emit lights dependent on a content of the partial input signal, respectively. The emitted lights are radiated from each of the light emitting diode arrays to a corresponding space modulation matrix, through which the radiated lights are transmitted dependent on the information pattern. The transmitted lights are received by each of the plural optical detector arrays, from which electric signals according to the partial input signal and the information pattern are supplied to the differential amplifiers, so that the differential electric signals are generated in the differential amplifiers by the electric signals from the plural optical detector arrays. Then, the thresholding of the differential electric signals is carried out in the thresholding devices to generate a pattern signal which is supplemental to the partial input signal, wherein the pattern signal is based on an information pattern selected from the information patterns of the plural space modulation matrices. The supplemental pattern signal is combined in the output terminals to the partial input signal, so that a complete output signal is supplied from the output terminals. Therefore, a pattern which is most similar to an incomplete input pattern can be selected from plural patterns previously stored in the space modulation matrices.
However, the neurocomputer has a disadvantage in that new information can not be written into the space modulation matrix by erasing the formerly stored information, since the space modulation matrix stores the information in the form of the white and black glass dry plates. Therefore, the degree of freedom is lowered in a practical use of the neurocomputer, since white and black glass dry plates providing a predetermined mask pattern must be newly prepared.